Ozone-destroying chemical still floating around; no one knows the source

25 years after it was banned, carbon tetrachloride isn't going away quickly.

Yesterday, NASA announced that its scientists have studied the unexpected persistence of an ozone-destroying chemical and have come to the conclusion that there must be some unidentified source of the substance. The item in question, carbon tetrachloride (CCl4), was banned in 1989 as part of the Montreal Protocol, which was intended to reduce the levels of ozone-destroying chemicals in the atmosphere.

In general, the protocol has worked; atmospheric levels of the chemicals covered by the treaty have dropped, and there are indications that Antarctica's annual ozone hole has stabilized. Levels of carbon tetrachloride have also dropped. The hitch is that they're not dropping as fast as we think they should, based on what we know of atmospheric chemistry.

That situation implies that we have one of two things wrong: either there are sources of the chemical that are still leaking it into the atmosphere, or our understanding of what's going on in the atmosphere is wrong. But NASA scientists have now taken data about existing sources and plugged them into a chemistry-climate model and concluded that the data best fits an unknown source. By their own admission, the scientists are mystified about what that source could be. Qing Liang of NASA's Goddard Space Flight Center was quoted as saying, "It is now apparent there are either unidentified industrial leakages, large emissions from contaminated sites, or unknown CCl4 sources."

Given that carbon tetrachloride is a neurotoxin and causes liver disease, it's generally a highly regulated substance. So the source might be found in locations where regulation is lax, making identifying the source that much more of a challenge.

Carbon Tet. We also had one of those old brass tube filled (like a giant syringe!) with it as a fire extinguisher. I believe the delightful chemical was the source of many pediatric poisonings, kids got into the "spot remover".

For all those climate-change deniers who like to roll out that old ignorant chestnut, "Butbutbut the planet is so huge, humans couldn't possibly do anything to influence the atmosphere!" you have here proof that people can, in fact, affect the environment on a massive scale.

And you also have proof that when we choose to stop doing damage, that can work, too.

So please, for fuck's sake, stop trying to use that fallacy. Pick another one for us to debunk and let us skip a step next time.

For those suggesting landfills as the probable cause: the models used by scientists are based on "production" data, and this already includes anything that would in the end go in a landfill.

The issue here is that the amount of material "produced" befre the ban,wherever it could still be now, is not enough to explain the slow instead of rapid decline.

And it puzzles me that a single source could be the cause: even a huge megafactory producing only this wouldn't be enough to tip the scale on a global level, so it is a widespread problem or at least a problem with some countries not doing whatis expected from them

Well, what about developing countries that don't tend to worry about environmental regulations that much. Who all signed on to the Montreal Protocol? (find it hard to believe that every country in the world did). Or, better yet, who didn't sign on to it?

Edit: Turns out everyone in the UN has ratified it, which surprised me. So I'll have to agree with the comment above mine in that case.

Back when intn'l cooperation to save this planet was still possible (read: over corporate and national economical interests).

The truth is, the chemical companies knew that alternatives were available and they could make as much money or more off them as they did off the banned ones. Industry doesn't mind substitution, what they hate is imposition. They'll substitute one chemical for another, but they won't add something like filters or scrubbers that they see as purely cost with no profit angle.

Of course they won't because business in business to turn a profit. They're not in business to lose money and adding cost to the production of their product is nonsensical UNLESS that cost is uniformly applied to everyone making that product. There are two ways to make that happen: (1) government regulation or (2) organized activism such as social media. Don't like monsanto? Don't buy their products (good luck). Don't like big oil (integrated majors), don't buy gasoline (good luck again- and what about the rare earth mining to make those AC induction motors and those batteries?)

Soooo...working it back the other way...$45M represents 1.4851% of the $3.03T and 1.4851% of $120K is.... $1782.18...which is $282 more than most folks carry in their pocket....but in 30 more years it may be about right.

And it had a very pleasant smell, from what I remember from my boyhood trips to the laundromat/dry-cleaners to carry laundry for grandma, playing Galaga while the washers spun. Sweet and crisp, like sugary ozone...

Given that carbon tetrachloride is a neurotoxin and causes liver disease, it's generally a highly regulated substance.

Gee, we used it in High School Chemistry. Then again, we played with mercury then with our bare hands, too.

It never ceases to amaze me WTF we used to think would be a good idea.

Given that we can look back and see such things everywhere we look, it makes one wonder what else we are doing currently that is bat-shit insane.

I bet some of the food additives designed to have little to no nutritional value make next centuries list. There are a few current medical procedures which seem a little questionable as well.

My sister (a physician) is convinced that most people that believe they are feeling better from gluten-free diets are actually feeling better from less-preservatives diets, as there is a high correlation between gluten-free products and preservative-free products. She actually has a hypothesis of which preservatives are doing it, I just don't remember the names right now.

Her backup hypothesis is that people who feel better with gluten-free diets are actually feeling better from low-refined-carbohydrate diets.

Of course, there are some people with celiac disease, but the rate of gluten-sensitivity claimed in the population in the last few years dramatically out-paces the number of people who could reasonably be expected to have celiac disease. Some of the non-celiac people claiming sensitivity to gluten may just be sensitive to something that's correlated to gluten.

For all those climate-change deniers who like to roll out that old ignorant chestnut, "Butbutbut the planet is so huge, humans couldn't possibly do anything to influence the atmosphere!" you have here proof that people can, in fact, affect the environment on a massive scale.

How do we know this isn't a lie, also? Of course the climate change guys would have to get the other planetary researchers in on the scam, in order to show similar global-scale effects. Just to keep the scam from being too obvious. But if you're an astute observer like myself, you'd see through all of that bull shit. [/s]

Given that carbon tetrachloride is a neurotoxin and causes liver disease, it's generally a highly regulated substance.

Gee, we used it in High School Chemistry. Then again, we played with mercury then with our bare hands, too.

It never ceases to amaze me WTF we used to think would be a good idea.

Reminds me of that line from MIB: "Fifteen hundred years ago everybody knew the Earth was the center of the universe. Five hundred years ago, everybody knew the Earth was flat, and fifteen minutes ago, you knew that humans were alone on this planet. Imagine what you'll know tomorrow."

Forty years ago we knew carbon tetrachloride was safe enough to use in High School Chemistry classes.

I totally agree with the point you're making, but do feel the need to point out that people have known the Earth was round for a lot longer than that.

For all those climate-change deniers who like to roll out that old ignorant chestnut, "Butbutbut the planet is so huge, humans couldn't possibly do anything to influence the atmosphere!" you have here proof that people can, in fact, affect the environment on a massive scale.

How do we know this isn't a lie, also? Of course the climate change guys would have to get the other planetary researchers in on the scam, in order to show similar global-scale effects. Just to keep the scam from being too obvious. But if you're an astute observer like myself, you'd see through all of that bull shit. [/s]

sad but true. and it's worth remembering that many of the older shills got their start denying the CFC-ozone hole connection back in the day.

Methyl Bromide was supposedly banned by the Montreal Protocol. But every year a critical use exemption for it is granted for fruit fumigation. The best part is after the fruit is gassed the methyl bromide is not recovered its just released to the atmosphere. They release thousands of pounds of it ever week where I work.

They're trying to limit CO2 emissions, and I wonder how much is released by the carbonated beverage industry.

Actually not much to the best of my knowledge. A lot less than you simple exhale.

On an interesting note, most bigger breweries actually capture some of the CO2 produced during fermentation to later force carb their beers once they bottle them. Not sure what they do with the excess CO2 (they very well might capture it and sell it, but probably not).

I once took a tour of a brewery and there was a CO2 truck (like a propane truck, only for CO2) parked outside. I assumed it was making a delivery, but for all I know it could have been picking some up.

What is it used for? In other words, what type of industry might we be contemplating is still illegally using/misusing this substance?

Mainly as dry cleaning fluid. Which leads me to suspect that most of emissions unaccounted for are slowly evaporating fumes from ground contamination and old waste sites (legal or illegal) that stored tons of the stuff.

The substance was used globally in what must have been at least hundreds of thousands of locations, most poorly regulated and in a time when dumping was common.

So I think the most plausible explanation it that.

Compare this to the very successful banning and reduction of other Montreal Substances used primarily in industry such as chlorinated and fluorinated hydrocarbons, and it suggests the less regulated environment of small business might be at fault.

Some web searches seem to indicate that carbon tetrachloride's use as a degreasing agent or solvent can be used in oil or natural gas extraction, for example in oil sands or fracking situations. In 2012 a chemical company dumped 163 tonnes of carbon tetrachloride in an abandoned asphalt concrete plant in Balezino, Russia but they got caught; I wonder how many other industrial-scale illegal dumps have gone unnoticed. I wonder if we'll be able to use UAV's to identify CCl4 in the air and localize its source.

Soooo...working it back the other way...$45M represents 1.4851% of the $3.03T and 1.4851% of $120K is.... $1782.18...which is $282 more than most folks carry in their pocket....but in 30 more years it may be about right.

Your maths is out by three orders of magnitude.

Three trillion is 3,000,000,000,000 not 3,000,000,000.

So $45m to the USA would be like $1.75 to someone earning $120k per year.

I don't know very many people who earn $120k / year. Average income in the USA seems to be somewhere between $38k and $28k/ year depending on how it's measured (numbers are skewed by a small number of extremely high earners) - so you might be better off using a lower number.

Given that carbon tetrachloride is a neurotoxin and causes liver disease, it's generally a highly regulated substance.

Gee, we used it in High School Chemistry. Then again, we played with mercury then with our bare hands, too.

It never ceases to amaze me WTF we used to think would be a good idea.

Reminds me of that line from MIB: "Fifteen hundred years ago everybody knew the Earth was the center of the universe. Five hundred years ago, everybody knew the Earth was flat, and fifteen minutes ago, you knew that humans were alone on this planet. Imagine what you'll know tomorrow."

Forty years ago we knew carbon tetrachloride was safe enough to use in High School Chemistry classes.

I totally agree with the point you're making, but do feel the need to point out that people have known the Earth was round for a lot longer than that.

we know where its coming from. Texas. like the exploding fertilizer plant where owners killed lots of workers because regulation and EPA is bad.Just look to where 'regulation' isn't enforced, and the largest number of people are murdered by industry 'libertarians'.

What is it used for? In other words, what type of industry might we be contemplating is still illegally using/misusing this substance?

In organic chemistry class (1984), it was used in nmr spectroscopy. I am not sure if it is still used though.

Rarely. Most modern NMR spectrometers use the signal from deuterium in the solvent (usually deuterated chloroform, acetone, DMSO, or water) for calibration. And instruments without a deuterium lock channel are often used solventless, to allow for higher signal-to-noise ratio.

Some institutions use carbon tetrachloride as a solvent for infrared spectroscopy on solid organic materials (the SDBS in Japan has numerous carbon tetrachloride IR spectra posted).

In any case, it is unlikely that solvents used in spectroscopy experiments involved any significant fraction of the amount of carbon tetrachloride used for industrial purposes.

The chemistry department in which I work no longer has any carbon tetrachloride; when we did, it was used as a solvent for specific reactions, but has been replaced with dichloromethane or chloroform.

As an aside, while carbon tetrachloride is useful as an extinguisher for many types of chemical fire, its use for extinguishing fires involving sodium metal is a very bad idea.

What is it used for? In other words, what type of industry might we be contemplating is still illegally using/misusing this substance?

In organic chemistry class (1984), it was used in nmr spectroscopy. I am not sure if it is still used though.

Rarely. Most modern NMR spectrometers use the signal from deuterium in the solvent (usually deuterated chloroform, acetone, DMSO, or water) for calibration. And instruments without a deuterium lock channel are often used solventless, to allow for higher signal-to-noise ratio.

Some institutions use carbon tetrachloride as a solvent for infrared spectroscopy on solid organic materials (the SDBS in Japan has numerous carbon tetrachloride IR spectra posted).

In any case, it is unlikely that solvents used in spectroscopy experiments involved any significant fraction of the amount of carbon tetrachloride used for industrial purposes.

The chemistry department in which I work no longer has any carbon tetrachloride; when we did, it was used as a solvent for specific reactions, but has been replaced with dichloromethane or chloroform.

As an aside, while carbon tetrachloride is useful as an extinguisher for many types of chemical fire, its use for extinguishing fires involving sodium metal is a very bad idea.

Thanks for the update. It has been about thirty years since I was tasked with organic structure determination and building compounds from two carbon alcohols or less. Interesting about the carbon tetrachloride for fires; I also anticipate problems there. Do they also use that to stop magnesium-halide fires such as a grignard addition gone bad?

What is it used for? In other words, what type of industry might we be contemplating is still illegally using/misusing this substance?

In organic chemistry class (1984), it was used in nmr spectroscopy. I am not sure if it is still used though.

Rarely. Most modern NMR spectrometers use the signal from deuterium in the solvent (usually deuterated chloroform, acetone, DMSO, or water) for calibration. And instruments without a deuterium lock channel are often used solventless, to allow for higher signal-to-noise ratio.

Some institutions use carbon tetrachloride as a solvent for infrared spectroscopy on solid organic materials (the SDBS in Japan has numerous carbon tetrachloride IR spectra posted).

In any case, it is unlikely that solvents used in spectroscopy experiments involved any significant fraction of the amount of carbon tetrachloride used for industrial purposes.

The chemistry department in which I work no longer has any carbon tetrachloride; when we did, it was used as a solvent for specific reactions, but has been replaced with dichloromethane or chloroform.

As an aside, while carbon tetrachloride is useful as an extinguisher for many types of chemical fire, its use for extinguishing fires involving sodium metal is a very bad idea.

Thanks for the update. It has been about thirty years since I was tasked with organic structure determination and building compounds from two carbon alcohols or less. Interesting about the carbon tetrachloride for fires; I also anticipate problems there. Do they also use that to stop magnesium-halide fires such as a grignard addition gone bad?

Whether carbon tetrachloride was used, it would have depended on whether the person trying to extinguish the fire understood the chemistry.

In a Grignard, either the magnesium or the ether is on fire. Carbon tetrachloride might extinguish an ether fire, but it might react with the magnesium. If the magnesium itself is on fire, the problem is different. Magnesium fires are not readily extinguished, even with modern class D extinguishers.

What is it used for? In other words, what type of industry might we be contemplating is still illegally using/misusing this substance?

In organic chemistry class (1984), it was used in nmr spectroscopy. I am not sure if it is still used though.

Rarely. Most modern NMR spectrometers use the signal from deuterium in the solvent (usually deuterated chloroform, acetone, DMSO, or water) for calibration. And instruments without a deuterium lock channel are often used solventless, to allow for higher signal-to-noise ratio.

Some institutions use carbon tetrachloride as a solvent for infrared spectroscopy on solid organic materials (the SDBS in Japan has numerous carbon tetrachloride IR spectra posted).

In any case, it is unlikely that solvents used in spectroscopy experiments involved any significant fraction of the amount of carbon tetrachloride used for industrial purposes.

The chemistry department in which I work no longer has any carbon tetrachloride; when we did, it was used as a solvent for specific reactions, but has been replaced with dichloromethane or chloroform.

As an aside, while carbon tetrachloride is useful as an extinguisher for many types of chemical fire, its use for extinguishing fires involving sodium metal is a very bad idea.

Thanks for the update. It has been about thirty years since I was tasked with organic structure determination and building compounds from two carbon alcohols or less. Interesting about the carbon tetrachloride for fires; I also anticipate problems there. Do they also use that to stop magnesium-halide fires such as a grignard addition gone bad?

Whether carbon tetrachloride was used, it would have depended on whether the person trying to extinguish the fire understood the chemistry.

In a Grignard, either the magnesium or the ether is on fire. Carbon tetrachloride might extinguish an ether fire, but it might react with the magnesium. If the magnesium itself is on fire, the problem is different. Magnesium fires are not readily extinguished, even with modern class D extinguishers.

I apologize for not making part of my question more clear. When you wrote "As an aside, while carbon tetrachloride is useful as an extinguisher for many types of chemical fire, its use for extinguishing fires involving sodium metal is a very bad idea," why would that option even have been considered with a reactive metal? Again, it has been thirty years since the last time I have seen the inside of a chemistry class and thanks for your time.

What is it used for? In other words, what type of industry might we be contemplating is still illegally using/misusing this substance?

In organic chemistry class (1984), it was used in nmr spectroscopy. I am not sure if it is still used though.

Rarely. Most modern NMR spectrometers use the signal from deuterium in the solvent (usually deuterated chloroform, acetone, DMSO, or water) for calibration. And instruments without a deuterium lock channel are often used solventless, to allow for higher signal-to-noise ratio.

Some institutions use carbon tetrachloride as a solvent for infrared spectroscopy on solid organic materials (the SDBS in Japan has numerous carbon tetrachloride IR spectra posted).

In any case, it is unlikely that solvents used in spectroscopy experiments involved any significant fraction of the amount of carbon tetrachloride used for industrial purposes.

The chemistry department in which I work no longer has any carbon tetrachloride; when we did, it was used as a solvent for specific reactions, but has been replaced with dichloromethane or chloroform.

As an aside, while carbon tetrachloride is useful as an extinguisher for many types of chemical fire, its use for extinguishing fires involving sodium metal is a very bad idea.

Thanks for the update. It has been about thirty years since I was tasked with organic structure determination and building compounds from two carbon alcohols or less. Interesting about the carbon tetrachloride for fires; I also anticipate problems there. Do they also use that to stop magnesium-halide fires such as a grignard addition gone bad?

Whether carbon tetrachloride was used, it would have depended on whether the person trying to extinguish the fire understood the chemistry.

In a Grignard, either the magnesium or the ether is on fire. Carbon tetrachloride might extinguish an ether fire, but it might react with the magnesium. If the magnesium itself is on fire, the problem is different. Magnesium fires are not readily extinguished, even with modern class D extinguishers.

I apologize for not making part of my question more clear. When you wrote "As an aside, while carbon tetrachloride is useful as an extinguisher for many types of chemical fire, its use for extinguishing fires involving sodium metal is a very bad idea," why would that option even have been considered with a reactive metal? Again, it has been thirty years since the last time I have seen the inside of a chemistry class and thanks for your time.

Although it is not clear that every fire extinguishing material is tested with all fires, there is a tendency to assume (by users) that a "chemical fire extinguisher" works for all chemical fires.

Of course this is not limited to fire extinguishers -- I saw someone use a squirt bottle to try to extinguish a fire; it did not work, since the squirt bottle contained ethanol.

The problem with the CFC ban is that it continues to cost lives, particularly in 3rd world countries, and there's no real evidence the ban saved any lives, nor that it was a serious problem.

CFC's were some of the most cost-effective fire retardants, medical sterilizers, and refrigerants in existence. This has less of an impact on the most developed countries, but in a country where cost is critical, poor refrigerants mean spoiled food, or even just lost food, which leads to starvation and disease. Same with fire retardants and sterilization.

The other side is that there really isn't much benefit to saving the ozone layer, because the effects were localized. Get this: the ozone degradation occurred only on the poles, where special windy weather conditions allowed the CFC's to climb to the atmosphere - nowhere else. The ozone hole could not expand beyond the poles either. No one lives directly on the poles, and there's not much of any kind of life there.

The CFC ban was simple: yet another rushed ban without a serious assessment of the consequences, and it cost real human lives for no net gain.

The third world countries were, for the most part, exempted from the Montreal Protocol; they could continue to make Freon even while the rich countries had to do without, since their volumes of use and production were small in comparison.

And it was believed that the ozone holes could easily spread to the rest of the atmosphere, with very serious consequences to many forms of life.